Is there a tool to convert from the brat standoff format to CoNLL-U format?
The brat annotation tool has provided some useful scripts for converting the annotations format including standoff format to CoNLL. Please see this source code from brat GitHub repo for converting the .ann and .txt inputs (standoff format) to .conll file: https://github.com/nlplab/brat/blob/master/tools/anntoconll.py